1. Technical Field
The present invention relates to a printing apparatus, a method of controlling a printing apparatus, and a control program of a printing apparatus.
2. Related Art
In a printing apparatus that forms an image on a medium by ejecting an ink from a nozzle, there is a case in which the ink is not normally ejected from the nozzle due to thickening of the ink. When ejection abnormality which is a state in which an ink is not normally ejected from a nozzle, that is, the ejection state of the ink from the nozzle becomes abnormal occurs, dots which are expected to be formed by the ink ejected from the nozzle are not formed and the quality of an image formed on a medium is degraded. In order to prevent degradation of the image quality caused by unformed dots, various techniques related to complement in which, in a case where ejection abnormality occurs in one nozzle, dots are formed by ejecting an ink from another nozzle instead of allowing the one nozzle to eject an ink have been suggested.
For example, a technique of complementing the nozzle with another nozzle by increasing the amount of ink to be ejected from another nozzle adjacent to the one nozzle in the case where ejection abnormality occurs in one nozzle is suggested in JP-A-9-024609.
Further, a technique of complementing the one nozzle with another nozzle by increasing the amount of ink to be ejected from another nozzle ejecting another color of ink in a case where ejection abnormality occurs in one nozzle ejecting one color of ink is suggested in JP-A-2004-174816.
As disclosed in JP-A-9-024609, in the case where one nozzle is complemented with another nozzle adjacent to the one nozzle, dots formed by another nozzle are formed in a position different from that of dots formed by the one nozzle. That is, the complementing method disclosed in JP-A-9-024609 is not suitable for a printing process for which accuracy in a position or a shape of an image to be formed on a medium is required such as in a case of printing a bar code or a blueprint. That is, in the case where an image for which accuracy in the position or the shape thereof is required is printed, the image quality of the image to be printed is further degraded when the complementation is performed compared to a case where the complementation is not performed.
Further, as the technique disclosed in JP-A-2004-174816, in the case where one nozzle is complemented with another nozzle ejecting an ink having a color different from that of the ink ejected from the one nozzle, the color of dots formed by another nozzle becomes different from the color of dots formed by the one nozzle. That is, the complementing method disclosed in JP-A-2004-174816 is not suitable for a printing process for which accuracy in a color of an image to be formed on a medium is required such as a case of printing a photo. That is, in the case where an image for which accuracy of the color thereof is required is printed, the image quality of the image to be printed is further degraded when the complementation is performed compared to a case where the complementation is not performed.
As described above, in the case where nozzles are complemented in a printing apparatus according to a single complementing method, the image quality of an image to be formed on a medium may be further degraded when compared to an image to be formed when ejection abnormality has not occurred (in the case where nozzles are not complemented).
Further, in the case where a nozzle is complemented in a printing apparatus according to a single complementing method, when ejection abnormality occurs in another nozzle for complementing one nozzle in which ejection abnormality occurs, the complementation cannot be performed. In the case where complementation cannot be carried out although that ejection abnormality occurs, the image quality of an image is further degraded compared to an image to be formed in the case where ejection abnormality has not occurred.